| Hormones are a kind of small molecules which have physiological activity and play important roles in the entire life whether for plants or animals.However,the concentrations of hormones usually occur at extremely low levels,and the sample matrices are very complex.Therefore,it is necessary to develop an analytical method for the maximum improvement of its analytical sensitivity.In response this need,an effective sample pretreatment technique is often employed prior to analysis.Among the sample treatment techniques,solid phase extraction（SPE）is a well-established technique and has been applied for pre-concentration and cleaning-up of different compounds in complex matrices.In SPE technique,the sorbent is a very key factor owing to it is related to the analytical sensitivity,precise,and selectivity.Polymer,a kind of macromolecular material that possesses a flexible structure,designable monomer and tailored recognized sites.Nowadays,it has also been tried to use as sorbent to enrich kinds of analytes in complex samples.In this dissertation,different polymer sorbent materials were designed and synthesized to enrich the hormonal substances in complex matrices.Specific research contents are as follows:1、The magnetic polyhedral oligomeric silsesquioxane core-shell composite material was facilely constructed by thermally initiated free radical polymerization with Fe3O4 as the core and octavinyl polyhedral oligomeric silsesquioxane as the shell.The resultant composite material was characterized by Fourier transform infrared spectroscopy,Thermogravimetric analysis,Scanning electron microscopy,Transmission electron microscopy,Contact angle experiment and Nitrogen gas adsorption–desorption isotherm test.The composites was used to enrich estrogens in complex matrices based on the hydrophobicity interaction mechanism.The factors such as extraction time,salt concentration,sample p H,and amount of adsorbent were optimized by response surface methodology.Finally,the proposed method was applied for the determination of five estrogens from urine and Yellow River water samples.2、A novel nitrogen-rich hyperbranched polymer was synthesized by one-step precipitation copolymerization strategy.We developed in-pipet-tip SPE using this hyperbranched polymer material as sorbent for the enrichment of plant hormones with carboxyl functional groups based on electrostatic and hydrophobicity interaction mechanism.Our results showed that this hyperbranched polymer has large adsorption capacity and can effectively enrich the target analytes.Subsequently,we established a sensitive analysis method using this SPE procedure coupled with HPLC-UV.Finally,it was successfully used to determine plant hormones in fruits and vegetables. |
